Devices for determining a state of a magnetic field-generating article are provided. In various embodiments, a device comprises: a single crystal diamond having a plurality of NV centers, the single crystal diamond configured to be disposed adjacent to a magnetic field-generating article, and configured to generate a fluorescent signal in response to being illuminated by a light source; a coherent light source configured to generate a light beam directed at the single crystal diamond; a microwave (MW) radiation source configured to irradiate the single crystal diamond with a MW signal; a magnetic field source configured to apply a bias magnetic field to the single crystal diamond; a photosensor configured to collect the fluorescent signal generated by the single crystal diamond; and a computing node operatively coupled to each of the coherent light source, the MW radiation source, the magnetic field source, and the photosensor.

A Hall sensor has at least four sensor terminals for connecting the Hall sensor and a plurality of Hall sensing element shaving element terminals. The Hall sensing elements are interconnected with the element terminals in a connection grid in between the sensor terminals, the connection having more than one dimension. The Hall sensing elements are physically arranged in an arrangement grid having more than one dimension and being different from the connection grid. At least some of the Hall sensing elements are connected to at least two adjacent Hall sensing elements in the connection grid.

A Hall sensor has at least four sensor terminals for connecting the Hall sensor and a plurality of Hall sensing element shaving element terminals. The Hall sensing elements are interconnected with the element terminals in a connection grid in between the sensor terminals, the connection having more than one dimension. The Hall sensing elements are physically arranged in an arrangement grid having more than one dimension and being different from the connection grid. At least some of the Hall sensing elements are connected to at least two adjacent Hall sensing elements in the connection grid.

Provided is a measurement device including an application unit, a detection unit, and a calculation unit. The application unit applies a first magnetic field, which is generated by applying a pulse current to a coil or applying currents with a plurality of frequencies to the coil in order, to an object. The detection unit detects a second magnetic field which is generated by applying the first magnetic field to the object. The calculation unit calculates a distribution of a magnetic field source m in the second magnetic field. The calculation unit may further generate an imaging signal for displaying the calculated distribution of the magnetic field source m, as an image. The display unit displays the image indicating the distribution of the magnetic field source m by using the imaging signal.

Provided is a measurement device including an application unit, a detection unit, and a calculation unit. The application unit applies a first magnetic field, which is generated by applying a pulse current to a coil or applying currents with a plurality of frequencies to the coil in order, to an object. The detection unit detects a second magnetic field which is generated by applying the first magnetic field to the object. The calculation unit calculates a distribution of a magnetic field source m in the second magnetic field. The calculation unit may further generate an imaging signal for displaying the calculated distribution of the magnetic field source m, as an image. The display unit displays the image indicating the distribution of the magnetic field source m by using the imaging signal.

A method of calibrating a network of magnetometers (C1, Ci) including the displacement of a magnet holder tool (10) above the network, and solving an optimisation problem to determine a localisation of the magnetometers in the network. This localisation minimises based on an optimisation criterion, the difference between a real attribute (D, m1, m2) of the magnet holder tool and an estimate of the attribute determined without knowledge of the displacement, starting from the localisation and measurements made by the magnetometers in the network during the displacement.

Systems and methods are disclosed for generating a magnetic fingerprint map. Information representing orientation and position of each portable device is obtained along with magnetic field measurements that are correlated with positions determined from the information. Uncertainties associated with the magnetic field measurements are estimated and the magnetic field measurements and associated uncertainties are converted from a device frame to a unified fingerprint frame using the orientations determined from the information. Parameters of a probability distribution function for magnetic field measurements and contaminating measurements are mitigated at each determined position based at least in part on the converted magnetic field measurements and associated uncertainties. Correspondingly, the magnetic fingerprint map is generated from the determined parameters of the probability distribution functions.

Systems and methods are disclosed for generating a magnetic fingerprint map. Information representing orientation and position of each portable device is obtained along with magnetic field measurements that are correlated with positions determined from the information. Uncertainties associated with the magnetic field measurements are estimated and the magnetic field measurements and associated uncertainties are converted from a device frame to a unified fingerprint frame using the orientations determined from the information. Parameters of a probability distribution function for magnetic field measurements and contaminating measurements are mitigated at each determined position based at least in part on the converted magnetic field measurements and associated uncertainties. Correspondingly, the magnetic fingerprint map is generated from the determined parameters of the probability distribution functions.

Various embodiments are directed to a method and system for mapping or visualizing the magnetic fields and their associated field strengths of an object, such as a mobile computing device. An example source of the magnetic fields may be a near-field communication (NFC) reader configured in the object. A computer vision system or device may track a visual marker arranged near or on a magnetic field strength detector in order to associate, match, or map the magnetic field strength measurement readings of the detector at different positions or locations on the object. The computer vision system may generate and display a heat map of the object based on at least the magnetic field strength measurements and their relative positions.

Various embodiments are directed to a method and system for mapping or visualizing the magnetic fields and their associated field strengths of an object, such as a mobile computing device. An example source of the magnetic fields may be a near-field communication (NFC) reader configured in the object. A computer vision system or device may track a visual marker arranged near or on a magnetic field strength detector in order to associate, match, or map the magnetic field strength measurement readings of the detector at different positions or locations on the object. The computer vision system may generate and display a heat map of the object based on at least the magnetic field strength measurements and their relative positions.